Several factors to consider when selecting gear materials

Several major factors to be considered in the selection of gear materials: precision transmission, gear speed, impact load, load size and media. The relevant instructions are as follows, for reference.

1. Precision transmission:

In order to ensure that the gear transmission is stable and noise-free, the product must not only have high dimensional accuracy, but also have a stable size.Quenching + high temperature tempering produces tempered sorbite, which not only has moderate hardness to improve gear precision, but also the tempered sorbite structure keeps the product dimensionally stable;

However, the gear surface needs to be wear-resistant and requires high hardness. For example, surface quenching or carburizing quenching can easily deform the product, resulting inPrecision gearNitriding treatment is often used, so the material should be nitrided steel or medium carbon chromium molybdenum steel.

2. Gear speed:

As the gear speed continues to increase, the fatigue failure of the product becomes the main contradiction; when the product speed is greater than 3000r/min, people call it high-speed gear.

According to a large number of previous research results, the hardness of low-carbon alloy steel is in the range of 30-35HRC, and the material has fatigue resistance. Therefore, in order to ensure the internal hardness of the gear, a structure that guarantees hardenability should be selected.

3. Impact load:

Impact load is likely to cause stress concentration in the stressed parts of the gear, which makes the material structure defects and gear manufacturing and processing defects more sensitive, so that the toughness of the material matrix is ​​particularly important. The low-carbon alloy steel has excellent toughness after quenching and tempering. Considering the gear High surface hardness requirements, so in the case of impact load, low-carbon alloy carburized steel becomes the material of choice.

4. Load size:

The size of the load directly determines the contact stress and bending stress that the gear bears. Increasing the yield strength and fatigue limit of the material is conducive to improving the life of the gear. In the absence of impact load, Q235B or Q345B material can be used for low load, and 45#, 40Cr can be used for high load. Or 40MnB material. 

5. Medium:

When gears are used in corrosive media, in principle, corrosion-resistant materials such as bronze or stainless steel should be selected.

There are several major factors to be considered in the selection of gear materials above, including but not limited to, if you have more questions or related processing requirements, you can consult EP for free.